Adapted from Ina Garten's Orzo with Roasted Vegetables.
Bring a large pot of water to a boil. Add salt and the orzo. Cook according to the box directions. Then drain and set aside to cool.
For the dressing, wisk together all ingredients. Pour 1/4 of the dressing over the pasta after drained so it can absorb while cooling.
Cut the eggplant into large slices and the peppers and onions into large chucks for grilling.
Drizzle with olive oil and sprinkle with salt and pepper.
Spray the grates of the grill with non-stick spray. Grill the vegetables for 4-5 minutes per side.
Remove from the grill and let cool until it is cool enough to handle. Chop into bite sized pieces and add to the pasta.
Pour on the remaining dressing and mix together.
Add in the feta and any of the optional toppings - scallions and pine nuts. Serve.